(a) Field of the Invention
The present invention relates to a liquid crystal display (LCD), more specifically to an LCD having an electrode array for generating electric fields in a signal substrate.
(b) Description of the Related Art
A liquid crystal display having an electrode array for generating an electric field which is parallel to both substrates (IPS-mode in-plane switching mode) is described in U.S. Pat. No. 5,598,285. However, this IPS-mode LCD has several problems.
The first problem is that the height difference of the two electrodes, a common electrode and a pixel electrode used for generating electric fields, causes uneven rubbing of an alignment layer, which results in the light leakage.
The second problem i s that the potential difference between a data line applying data signals to the pixel electrode, and the common electrode in the region between them may cause some light leakage and the light leakage is also causing the lateral cross talk.
To prevent any light leakage, the width of a black matrix along the perimeter of a pixel region may be widened, or the gap between the common electrode and the data line may be narrowed. However, the aperture ratio of the LCD is reduced when the black matrix is widened, And the common electrode and the data line may easily short when the gap between the common electrode and the data line is made smaller.
The third problem is that the contact property of pads connected to signal lines, which are usually made of an aluminum or an aluminum alloy having low resistivity, is poor, because the aluminum or aluminum alloy, when exposed, is easily oxidized.